NOTES. 
NOTE ON ME. BARBER’S PAPER ON PACHYTHECA.— 
Few fossils have been the subject of more varied explanation than 
Pachytheca . This has arisen from the fact that any positive indica- 
tions as to its structure have been so meagre. The careful investiga- 
tions of Mr. Barber tell us pretty well all that we are ever likely to 
know, and at any rate supply us with definite grounds for rejecting 
the greater part of the hypotheses which have been put forward with 
regard to it. 
More than ten years ago I carefully investigated the specimens of 
Pachytheca belonging to Sir Joseph Hooker at his request. I arrived 
at these conclusions : — (i) That the cortical cells branched, (ii) that 
the cortical cells and the medullary filaments were continuous, and 
(iii) that the structure of the whole organism was comparable with 
that of known Algal types. On the occasion of Sir W. Dawson’s 
paper on Prototaxites being read at the Geological Society, on Nov. 
1 6, 1 88 1, my friend, Prof. Judd, asked me to make some statement 
about Pachytheca. It will be convenient to reprint from the Pro- 
ceedings what took place. 
‘ Prof. Judd stated that he exhibited, on behalf of Mr. Thiselton- 
Dyer, two sections of Pachytheca. Mr. Thiselton-Dyer regretted 
that he was unable to be present at the Meeting, but had sent Prof. 
Judd a letter, from which he read the following extract : — 
“Kew, Nov. 15, 1881. 
“Some time ago Sir Joseph Hooker received from Mr. 
Grindrod a number of specimens of Pachytheca in situ on pieces 
of rock. As these examples of the fossils were apparently well 
preserved, two or three were detached and intrusted to Mr. 
Norman, who made the sections which are now in your hands. 
Sir Joseph Hooker did not see his way to any definite conclusion 
as regards the structure which they exhibited. He, however, 
allowed me to examine them, and they have since remained in 
my possession. The conclusion which I arrived at was that 
[Annals of Botany, Vol. V. No. XVIII. April, 1891.] 
Q % 
